現今青少年以靜態生活型態居多，不良健康飲食行為、身體活動量減少，導致體位異常與負面身體意象，可能威脅青少年健康。本研究旨在瞭解高雄市區某國中學生體位指標之現況，並探討八週健康飲食教育與身體活動介入之成效；介入結束後再行追蹤八週，以了解其維持效益。本準實驗設計研究以兩班 62位八年級學生為受試群體，其中體位過重與肥胖的學生兊 22人為受試對象；並將受試對象區分為健康飲食教育組與身體活動組。健康飲食教育組則以提供相關課程為主，身體活動組之介入方法以增刋 50%身體活動量為目標；所得資料包括受試對象的體位指標之身體質量指數、體脂率及腰圍。相關資料以 SPSS 18.0版進行資料分析，並以雙因子共變數分析等統計方法進行分析。研究結果顯示，約三分之一的國中生體位為過重及肥胖；國中階段學生之日常生活平均步數為5325±1912步；男學生為 5840±2016步、女學生為 4736±1663步。研究結果亦顯示，對就讀國中階段之青少年而言，女學生宜採提高身體活動量之策略、男學生則建議以健康飲食教育介入，對短期的體重控制有較顯著的效益。在維持成效上，身體活動組的男學生其身體質量指數與體脂率之控制皆優於女學生；且不論男女學生，身體活動組的體脂率與腰圍的控制成效皆優於飲食教育組。研究者認為，增加身體活動量或提供健康飲食相關資訊，對國中學生體位控制上有不同的時間效應；家長或教育人員需在不同的時期內採取不同的行動策略，對體位控制方能有其效益。

Background: Nowadays, most adolescences beings have sedentary lifestyles. Inactivity and Poor eating habits during adolescent set the stage for health problems in adulthood. The purposes of this study aim to investigate effects of different intervention on overweight and obese Junior high school students’ body compositions and to examine the effect of follow-up assessment. In this quasi experimental design study, 62 eighth-grade students were recruited in the initial stage, and 22 of them were overweight and obese. These subjects were divided into two classes with different interventions: to provide health-diet education or to improve their physical activity. Students in the physical activity group were encouraged to enhance their physical activities up to 150% than usual, while students in the other group received 8-classes of health-diet education. Data were collected at the baseline, posttest and the follow-up period, which included subjects’ height, weight, body fat percentage and waist circumference. All data was analyzed by SPSS 18.0 for Windows with two factors ANCOVA. The results of this study were shown that over one third of 8-grade students were overweight and obese; the daily steps were 5325±1912, boys’ steps were 5840±2016 in average, girls’ were 4736±1663. Results of this study also indicated that girls in the physical-activities group could improve their body compositions than boys, while boys might have a better outcome in the healthy-diet group. Regarding the follow-up effect, subjects in the physical activities group might maintain an expected performance than the other group. The researcher suggests that parents and teachers may apply different strategies for adolescences to achieve the expected goal.